M2-like presynaptic receptors modulate acetylcholine release in the cockroach (Periplaneta americana) central nervous system

摘要: Abstract The effects of muscarinic agonists on the acetylcholine release in cercal-afferent giant-interneurone synapses cockroach ( Periplaneta americana ) were investigated using single-fibre oil-gap method. Pressure-ejection arecoline, carbachol and oxotremorine within sixth abdominal ganglion reduced cEPSP amplitude a concentration-dependent manner without any effect at postsynaptic site range concentrations used. A maximal inhibitory 56, 54 68% was estimated for oxotremorine, respectively. rank order potencies tested was: arecoline > oxotremorine. McN-A-343 bethanechol had an but higher doses also acted level. depressive only counteracted by AF-DX 116 methoctramine. In presence picrotoxin about 15%. It is concluded that central nervous system modulated functional M 2 -like presynaptic receptors. influence electrical activity this modulatory discussed.